Gastric Bypass Leads to Improvement of Diabetic Neuropathy Independent of Glucose Normalization - Results of a Prospective Cohort Study (DiaSurg 1 Study)

SLR- March 2014- Mitch Hulbert

Reference: Muller-Stich; BP. Fischer; L. Kenngott; HG. Gondan; M. Senfit; J. Clemens; G. Nickel; F. Fleming; T. Nawroth; PP. Buchler; MW. Gastric Bypass Leads to Improvement of Diabetic Neuropathy Independent of Glucose Normalization - Results of a Prospective Cohort Study (DiaSurg 1 Study). Annals of Surgery 2013 Nov; 258(5) 760-6.

Scientific Literature Review

Reviewed by: Mitch Hulbert, DPM
Residency Program: Columbia-St. Mary’s Hospital, Milwaukee WI

Podiatric Relevance: This article demonstrates evidence of improvement of HbA1c and neuropathy in patients that underwent a Roux-en-YGastric Bypass (RYGB) in patients with type 2 diabetes mellitus (T2DM). This is an interesting finding in that it had previously been published that the RYGB causes improvement of hypertension and dyslipidemia early after surgery independent of weight reduction. Although HbA1c and BMI were expected to improve with weight reduction and reduction in caloric intake, this article shows evidence that neuropathy scores such as Neuropathy Symptom Score (NSS) and Neuropathy Deficit Score (NDS) improved significantly early after surgery, and prior to glucose normalization. 

Methods: This was a single armed prospective cohort study with 20 participants, all non-severely obese with insulin-dependent T2DM with BMI between 25 and 35 kg/m2 who underwent a RYGB as the method of their metabolic surgery. The aim was to evaluate the patients for improvement of distal peripheral neuropathy as an example of diabetes associated comorbidity. Post surgically they were evaluated using the NSS and NDS. 

Results:  Patients were followed postoperatively at three and six months. As expected, glucose control and insulin resistance improved, 13 patients became insulin free and six free of any anti-diabetic medications. Patients had a pre-operative mean HbA1c of 8.5 +/- 1.2 (7.0-10.9) and were measured again at six months showing 7.1 +/- 1.2 (5.8-9.6). Twelve of the 20 patients had neuropathy and ineach a NSS and NDS were obtained. Both scores reduced significantly six months after surgery. NSS decreased from a median of eight (range 0-10) to a median of 0 (Range 0-9), and the NDS from a median of six (Range 2-8) to a median of four(range 0-8). Eight of the 12 patients had a postoperative NSS of 0. No correlation between the reduction in the HbA1c and reduction in neuropathy was found. Symptomatic neuropathy was completely reversed in 67 percent of patients. 

Conclusions: The authors conclude that metabolic surgery has its risks, but the improvement in not onlyHbA1c and BMI, but also peripheral neuropathy scores is very promising. This could even point out that the complex metabolic effect may exceed glucose normalization. Although the sample size was small and follow-up short, these are promising results for a relatively simple surgery. Given the findings in this article, I will not specifically change my practice; but if this goes on to be proven in controlled trials surely I will become an advocate of the procedure in select patients.